Erythromelalgia

This rare disorder may be:

• Primary (cause unknown)

It may also be secondary to:

• Diabetes mellitus

• Gout

• Hypertension

• Lichen sclerosus

• Multiple sclerosis

• Myeloproliferative disorders (eg, polycythemia vera, thrombocythemia)

• Rheumatoid arthritis

• Spinal cord disorders

• Systemic lupus erythematosus

• Venous insufficiency

Less commonly, the disorder is related to the use of some medications (eg, nifedipine, bromocriptine). Less commonly, the disorder is related to the use of some medications (eg, nifedipine, bromocriptine).

A rare hereditary form of erythromelalgia starts at birth or during childhood.

Symptoms include burning pain, heat, and redness (in individuals with light skin) or a deepening of baseline coloration (in individuals with dark skin) in the feet or hands that lasts a few minutes to several hours. In most patients, symptoms are triggered by warmth (temperatures of 29 to 32° C) and are typically relieved by immersion in ice water. Trophic changes (thin, shiny, or discolored skin; hair loss; brittle nails) do not occur. Symptoms may remain mild for years or become severe enough to cause total disability. Generalized vasomotor dysfunction is common, and Raynaud phenomenon may occur.

Diagnosis of erythromelalgia is clinical (1). Testing is performed to detect causes. Genetic testing for a causative SCN9A mutation may be performed in primary erythromelalgia. Because erythromelalgia may precede a myeloproliferative disorder by several years, repeated blood counts may be indicated.

Differential diagnosis includes posttraumatic reflex dystrophies, shoulder-hand syndrome, peripheral neuropathy, causalgia, Fabry disease, and bacterial cellulitis.

Treatment of erythromelalgia is warmth avoidance, rest, elevation of the extremity, and application of cold (2). For primary erythromelalgia, multiple topical (eg, lidocaine, combination of amitriptyline and ketamine, midodrine, capsaicin, menthol) or oral (eg, mexiletine, carbamazepine) medications may be used. For secondary erythromelalgia, the underlying disorder is treated; ). For primary erythromelalgia, multiple topical (eg, lidocaine, combination of amitriptyline and ketamine, midodrine, capsaicin, menthol) or oral (eg, mexiletine, carbamazepine) medications may be used. For secondary erythromelalgia, the underlying disorder is treated;aspirin may be helpful when a myeloproliferative disorder is the cause. Gabapentin, venlafaxine, and sertraline may also be of benefit for both primary and secondary forms. may be helpful when a myeloproliferative disorder is the cause. Gabapentin, venlafaxine, and sertraline may also be of benefit for both primary and secondary forms.